Bandgap voltage generators are generally used to create a voltage which is equal to the bandgap potential of silicon devices at 0.degree. Kelvin. There are several basic techniques used to generate the bandgap voltage, which is approximately 1.2 volts. In one technique, equal currents are passed through two diodes of different size, while in another, different currents are passed through different, equal sized diodes. Both complementary metal-oxide semiconductor (CMOS) field-effect transistor (FET) based and bipolar transistor based bandgap reference generators are well documented in the available literature.
Unfortunately, traditional bandgap reference generators have certain inherent weaknesses. First, large amounts of DC gain are typically involved, rendering the generators highly sensitive to mismatches, particularly in critical voltage and current mirrors. Further, voltages applied to critical devices in the current mirror(s) are balanced at only one input voltage, and can be severely mismatched at normal operating voltage. This mismatch, in addition to disturbing base operating points, contributes to asymmetric stresses, thereby further aggravating sensitivity of the generator. Further, most CMOS field-effect transistor based bandgap reference generators are slow in start-up, resulting in minimal practical use, at least not without modification.
All of the above-noted weaknesses are addressed in a bandgap reference generator employing regulation and kick-start circuits embodying the concepts presented herein below.